In vitro analysis of antibacterial activity against wound pathogens, potential for wound healing, and anti‐melanoma properties of biosynthesized zinc oxide nanoparticles

Abstract Staphylococcus aureus is the most common cause of wound infections. Infected wounds increase wound severity and have a slower rate of healing. Moreover, emergence of multiple‐drug resistant bacteria such as methicillin‐resistant S. aureus (MRSA) limited treatment options. This study was therefore aimed to evaluate antibacterial activity against wound pathogen and wound‐healing properties of green synthesized ZnO nanoparticles derived from mangosteen peel crude extract (ZnO‐Gm). Moreover, their anti‐skin cancer activity was also investigated in vitro. As a result, the ZnO‐Gm particles significantly inhibited growth of S. aureus and MRSA with the IC50 values at 0.44 and 0.51 mg/mL, respectively. By performing quantitative reactive oxygen species (ROS) assay, the intracellular ROS in both treated S. aureus and MRSA with ZnO‐Gm was found to be significantly elevated. Furthermore, ZnO‐Gm exhibited cytotoxic effects via induction of apoptosis on the A375 melanoma cancer cell line, with an IC50 value of 8.91 µg/mL, while not affecting the normal cell line (Vero). In addition, 30 µg/mL of ZnO‐Gm could strongly promote wound healing of an epidermal keratinocyte cell line (HaCaT). Consequently, the findings of this study demonstrated that the green synthesized ZnO nanoparticles have potential as antibacterial agents, wound‐healing materials, and anti‐melanoma agents

Effects of Waste-Derived ZnO Nanoparticles against Growth of Plant Pathogenic Bacteria and Epidermoid Carcinoma Cells

Green synthesis of zinc oxide nanoparticles (ZnO NPs) has recently gained considerable interest because it is simple, environmentally friendly, and cost-effective. This study therefore aimed to synthesize ZnO NPs by utilizing bioactive compounds derived from waste materials, mangosteen peels, and water hyacinth crude extracts and investigated their antibacterial and anticancer activities. As a result, X-ray diffraction analysis confirmed the presence of ZnO NPs without impurities. An ultraviolet–visible absorption spectrum showed a specific absorbance peak around 365 nm with an average electronic band gap of 2.79 eV and 2.88 eV for ZnO NPs from mangosteen peels and a water hyacinth extract, respectively. An SEM analysis displayed both spherical shapes of ZnO NPs from the mangosteen peel extract (dimension of 154.41 × 172.89 nm) and the water hyacinth extract (dimension of 142.16 × 160.30 nm). Fourier transform infrared spectroscopy further validated the occurrence of bioactive molecules on the produced ZnO NPs. By performing an antibacterial activity assay, these green synthesized ZnO NPs significantly inhibited the growth of Xanthomonas oryzae pv. oryzae, Xanthomonas axonopodis pv. citri, and Ralstonia solanacearum. Moreover, they demonstrated potent anti-skin cancer activity in vitro. Consequently, this study demonstrated the possibility of using green-synthesized ZnO NPs in the development of antibacterial or anticancer agents. Furthermore, this research raised the prospect of increasing the value of agricultural waste

Potential usage of biosynthesized zinc oxide nanoparticles from mangosteen peel ethanol extract to inhibit Xanthomonas oryzae and promote rice growth

In recent decades, the biosynthesis of nanoparticles using biological agents, such as plant extracts, has grown in popularity due to their environmental and economic benefits. Therefore, this study investigated into utilizing ethanol crude extract sourced from mangosteen peel for the synthesis of zinc oxide nanoparticles (ZnO NPs) and assessing their efficacy against the rice blight pathogen (Xanthomonas oryzae pv. oryzae) through antibacterial evaluations. Additionally, the effects of the synthesized ZnO NPs on rice plant growth was investigated. The X-ray diffraction analysis revealed the production of wurtzite ZnO NPs under specific synthesis conditions, exhibiting a crystallite size of 38.71 nm (or 387.122 Å) without any contamination. Analysis of the ultraviolet–visible optical absorption spectrum indicated a characteristic absorption peak at 363 nm, suggesting a calculated band gap energy of 2.88 eV for the ZnO NPs. Furthermore, Fourier transform infrared spectroscopy analysis confirmed the presence of active compounds functional groups from mangosteen peel in the synthesized ZnO NPs. These biosynthesized ZnO NPs demonstrated significant inhibition of X. oryzae pv. oryzae growth, exhibiting an in vitro 50 % inhibitory concentration (IC50) value of 1.895 mg/mL and a minimum inhibitory concentration (MIC) value of 4 mg/mL. The ZnO NPs treatments at two-fold IC50 values significantly enhanced root length, dry biomass, and chlorophyll a content in rice plants. Consequently, the results demonstrated the potential application of biosynthesized ZnO NPs from mangosteen peel extract in green agriculture, as an alternative to excessive antibiotic use, for combating bacterial plant diseases, and for enhancing plant growth

Mechanistic study of Na-ion diffusion and small polaron formation in Krohnkite Na2Fe(SO4)(2)center dot 2H(2)O based cathode materials

Krohnkite-type Na2Fe(SO4)(2)center dot 2H(2)O mineral is a sustainable and promising polyanionic cathode that has been experimentally found to offer a high redox potential (3.25 V vs. Na/Na+) along with fast-ion diffusion and high reversibility. Owing to the structural complexity, Na+ diffusion was assumed to occur along a convoluted channel along the b-axis. However, theoretical work related to this material still appears missing to support that statement. In this work, DFT+U calculations have been performed with the primary aim to unveil the Na+ diffusion mechanism in this material. The electronic structure and charge transfer are also envisaged to reveal evidence of Fe2+/3+ redox reaction and a vital role of structural H2O. Based on formation energies of this material with varied Na concentration, a calculated voltage profile is determined to show two voltage plateaus at 4.81 and 3.51 V, corresponding to experimental results. Nudged elastic band calculation reveals that Na+ diffusion is primarily occuring in the 01 (1) over bar] direction with a moderate ionic mobility due to the structural distortion induced during migration, suggesting the possibility of defect-assisted diffusion. Intriguingly, the formation of small hole polarons is first observed, and could play a key role in the electronic conduction of this material

Miniaturized Metalens Based Optical Tweezers on Liquid Crystal Droplets for Lab-on-a-Chip Optical Motors

Surfaces covered with layers of ultrathin nanoantenna structures—so called metasurfaces have recently been proven capable of completely controlling phase of light. Metalenses have emerged from the advance in the development of metasurfaces providing a new basis for recasting traditional lenses into thin, planar optical components capable of focusing light. The lens made of arrays of plasmonic gold nanorods were fabricated on a glass substrate by using electron beam lithography. A 1064 nm laser was used to create a high intensity circularly polarized light focal spot through metalens of focal length 800 µm, N.A. = 0.6 fabricated based on Pancharatnam-Berry phase principle. We demonstrated that optical rotation of birefringent nematic liquid crystal droplets trapped in the laser beam was possible through this metalens. The rotation of birefringent droplets convinced that the optical trap possesses strong enough angular momentum of light from radiation of each nanostructure acting like a local half waveplate and introducing an orientation-dependent phase to light. Here, we show the success in creating a miniaturized and robust metalens based optical tweezers system capable of rotating liquid crystals droplets to imitate an optical motor for future lab-on-a-chip applications

Compensation in Al-Doped ZnO by Al-Related Acceptor Complexes: Synchrotron X-Ray Absorption Spectroscopy and Theory

The synchrotron x-ray absorption near edge structures (XANES) technique was used in conjunction with first-principles calculations to characterize Al-doped ZnO films. Standard characterizations revealed that the amount of carrier concentration and mobility depend on the growth conditions, i.e. H2 (or  O2)/Ar gas ratio and Al concentration. First-principles calculations showed that Al energetically prefers to substitute on the Zn site, forming a donor AlZn, over being an interstitial (Ali). The measured Al K-edge XANES spectra are in good agreement with the simulated spectra of AlZn, indicating that the majority of Al atoms are substituting for Zn. The reduction in carrier concentration or mobility in some samples can be attributed to the AlZn-VZn and 2AlZn-VZn complex formations that have similar XANES features. In addition, XANES of some samples showed additional features that are the indication of some α-Al2O3 or nAlZn-Oi formation, explaining their poorer conductivity